Water-coolant supply means for an outboard propulsion unit



J 5, 1965 c. F. ALEXANDER, JR 3,164,121

WATER-COOLANT SUPPLY MEANS FOR AN OUTBOARD PROPULSION UNIT Filed Sept. 28, 1962 if if A? INVENTOR.

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St2lt$ P2116 This invention relates to an outboard propulsion unit for watercraft and more particularly to a water-coolant supply means for such a unit.

, Water-coolant supply means are commonly provided in outboard propulsion units to provide the cooling water for circulation through the engine driving the unit and/ or portions of the unit. Generally the :inlet for the cooling Water is provided in the propulsion unit beneath the anticavitation plate or in the gear case housing or in the lower portion of the propulsion unit between the anti-cavitation plate and the gear case housing. For utility outboard propulsion unit operation wherein the lower portion of the unit including the anti-cavitation plate is normally submerged, inlets so disposed'are capable of providing an adequate supply of coolant.

Propulsion units for racing, however, usually operate under surface pitch. [conditions wherein the gear case housing may be wholly out of the water with only a portion of the propeller the water, presenting considerable difiiculty in obtaining an adequate supply of coolant. It

is generally an object of this invention to provide a coolant supply means for an outboard propulsion-unit which is better able toiprovide -an adequate supplyof coolant when operating at high speed under surface. pitch conditions. i

f Generally according to this invention, an adequatecoolant supply is provided by a water-coolant supply means in the outboard propulsion unit which includes provision for water inlet means spaced beneath thegear case housing in the skeg of the unit. With the water inlet placed in the skeg and in spaced relation beneath the gear case housing, the inlet will normally be submerged even when operating the propulsion unit at high speed under surface pitch conditions.

c The drawings furnished herewith illustrate the best mode of carrying out the invention as presently contemplated and described hereinafter: In the drawings:

FIGURE 1 is a side elevation of anoutboard motor a which employs the coolant supply means of this invention;

generally on line 3- -3 As shown in the drawings, the inventionis illustrated as applied to an outboard motor 1 having a drive shaft housing 2 supporting at the upper end thereof an engine,

not shown, enclosed within a cowl 3 and at-the opposite end thereof a lower housing 4. The motor 1 is removhor'montal plane on-the generally vertical swivel pin 9.

AN ourr FIG. 2 is an enlarged side elevation partially in seci tion of the lower portion of the outboard motor of FIG.

generallyon line 4+4 7 3,161,121 Patented Jan. 5, 1965 extends downwardly within housing 2 and strut portion 1t? and drivingly connects the engine with the generally chamber-19 is closed forwardly by a generally conically shaped end cap 21 which extends over the opening 22 to the chamber. The closure member 21) includes a forwardly extending stem portion 23 for securing the cap 21 in position over opening 22 with the stem portion being generally in alignment with the propeller shaft 14",

in gear chamber 17 and extending forwardly through the annular support sleeve 24 to properly center the stem portion within the coolant chamber.

The closure member 20 engages with shoulder 25' within gear chamber-17 to axially position the member within the gear case bore and is spaced axially .from support. sleeve 24 by means of an annular spool-like member 26 to be further described hereinafter. 'The closure member 29 along with the spool-like member 26 .and support sleeve 24 are secured within the coolant chamber 21 by means of the'zsnap ring 27 partially recessed in the wall of the gear case bore forwardly of the support sleeve. An'annular sealing member 28- is disposed in a peripheral recess 2t9formed between the spool-like member-26 and the adjacent stepped edge of olosure me'mber 20 to sealthe coolant chamber 19 from the gear'charnber 17.; V c

The end cap 21 serving as the forward closure for coolant chamber19 is secu red in position by the axially extending pin member 3%? which is threaded r 'earwardly thereof to'thre'adedly engage with a correspondingly threaded bore opening 31 in the forward end of stem portion 23 to secure the end cap over'the gear case open ing'22. Rearwardly the outside diameter of the end cap 21 correspond generally with th e outside diameter'of v gagement with the forward end edge'of the gear case'at opening 22 and an annular. flange ,33 inwardly "and rearwardly of shoulder '32 extends into gear case openingZZ and serves to properly alignthe' cap with respect to the gear case upon closure. 1

The skeg 12 beneath the gear case 11 is provided with a a coolant cavity Bd which receives the coolant, for circulation through the'inlet opening 35in. the leading orv for? ward edge of theskegand spaced beneath the'gear case. The coolant cavity 34 in sk'eg- 12 is provided with' a generally T-shaped cross sectioninterrnediate'the foreand-aft extremes thereof 'as is most clearlyvshow n in FIG. 3, The lower portion of cavity 34 is relatively narrow transversely so as to' mainta-in the' relatively nar-i row characteristic of the skeg. The upper relatively wide portion of cavity 34 extendsfbeneath thefigear case .11

The lower housing 4. includes the vertical strut portion 10 adapted at its upper end for securement to 'the drive 7 shaft housing 2, a gear case 11 beneath the strut portion, and a skeg 12 beneath the gear case. The drive shaft 13 1 and'beneath corresponding portions of coolant chamber I 19 and gear chamber 17 36 provided in the wallet. gear case 11 in alignment with the spool-like member 26-?andenters the peripheral recess i3? fornied'between the peripheral flanges 39S and 39 of c the spool-like member. Upon-entering .the'peripheral fi recess 37 of the spool-like member '26, the water is jco'n- K ductedinto the annular cavity-4t? around the stem por f From skeg cavity 3% the cooling'water is conducted i into the, coolant chamber 19 through a plurality of ports like member through a plurality of circumferentially spaced ports 41 in the annular Web portion 42 of the spool-like member, connecting flanges 33 and 39.

From the cavity' ttl interiorly of the spool-like member 26, the coolant moves into a generally frustoconical cavity 43 formed in the adjacent side of the centering support sleeve 24 and through the axially extending circumferentially spaced passage's'44 provided in sleeve 24 spaced intermediately between stem portion 23 and the wall of the gear case bore and into the forward portion of the coolant chamber 19.

After moving through gear case chamber 19, the water for cooling is conducted through the lower housing pas sage 45 communicating with chamber 19 to areas of the propulsion unit and/or engine where cooling is desired. A pump, not shown, maybe disposed in communication with passage 45 above the anti-cavitation plate 45 and be driven from drive shaft 13 to provide for circulation of coolant at the desired pressure.

' The lower housing 4 of this invention is particularly adapted for racing propulsion'units wherein the gear case 11 may be wholly out of the Water with the propeller 18 operating under surface pitch conditions as generally shown in FIG. 2. With the inlet opening 35 provided in the slreg 12 and spaced beneath the gear case 11, a substantially constant and adequate supply of coolant will be available in such racing units. During periods when the propulsion unit is operated at' racing speeds with gear case 11 wholly out of the water, the invention also provides for a degree of cooling for gear chamber 17 as the fresh circulating coolant flows around portions of the gear chamber through skeg-cavity 34 and coolant chamber19. Y

Various modes of carrying out the invention are contemplatedr as being within the scope of the following claims particularly pointing out and distinctly claiming the subjectgmatter which is regarded as the invention.

I claim: I I i 1. In an outboard propulsion unit for watercraft, said unit having a lower portion including a gear case for rotatably supporting a generally horizontal shaft carrying a propeller rearwardly of the gear case, a cooling water circulation system in said unit and including a hollow skeg extending downwardly from said gear case and having a heat exchange surfaceconstituting a wall of said gear case and water inlet means in said skeg supplying water to said system through the hollow interior of said skeg andspaced substantially beneath said gear case.

2. The invention as set forth in claim 1 wherein the water inlet means comprise at least one opening forwardly in said skeg.

3. The invention as set forth in claim 1 wherein the Water inlet means comprise at least one opening in the leading edge of said skeg.

4. In an outboard propulsion unit for Watercraft, said unit having a lower portion including a gear case and a slreg beneath said gear case, said gear case having a chamber rearwardly therein for rotatably supporting a generally horizontal shaft with the shaft projecting from the chamber and carrying a propeller rearwardly of the gear case and for housing the drive gears for said shaft; a cooling water circulationsystem in said unit and ineluding passage -means in said gear case forwardly of the gear chamber, a cavity in said skeg communicating with said passage means, said cavity comprising top and side Walls, said top wall constituting at least a portion of the bottom of the gear chamber and providing heat exchange means therebetween, and Water inlet means in the skeg opening into said chamber.

5. Theinvention as set forth in claim 4 wherein the skeg cavity is provided with a generally T-shaped crosssection with the relatively wide portion thereof extending beneath at least a-portion of said gear chamber to provide for a measure of cooling for said chamber when the propulsion unit is operated under surface pitch conditions with the gear case out of the water.

References (liter! in the file of this patent UNITED STATES PATENTS 1,893,662 Smith Jan. 10, 1933 2,847,967 Kiekhaefer Aug. 19, 1958 

1. IN AN OUTBOARD PROPULSTION UNIT FOR WATERCRAFT, SAID UNIT HAVING A LOWER PORTION INCLUDING A GEAR CASE FOR ROTATABLY SUPPORTING A GENERALLY HORIZONTAL SHAFT CARRYING A PROPELLER REARWARDLY OF THE GEAR CASE, A COOLING WATER CIRCULATION SYSTEM IN SAID UNIT AND INCLUDING A HOLLOW SKEG EXTENDING DOWNWARDLY FROM SAID GEAR CASE AND HAV- 